Small molecule donors based on benzodithiophene and diketopyrrolopyrrole compatible with both fullerene and non-fullerene acceptors

Abstract

Herein, two small molecule donors, BDTTT-DPP and BDTTVT-DPP, compatible with both fullerene and non-fullerene acceptors were developed. Both molecules exhibited medium bandgaps with complementary absorption to and appropriate energy level offsets with typical acceptors like PC₆₁BM and IDIC. The optimized devices showed the best power conversion efficiency (PCE) of 5.53% for fullerene organic solar cells and 5.48% for non-fullerene organic solar cells. Moreover, ternary devices containing blends of the small molecule donors, IDIC and PC₆₁BM produced PCEs of 6.53% for BDTTT-DPP cells and 6.55% for BDTTVT-DPP cells, even higher than the binary ones.